/* 定时器 */

#include "bootpack.h"

#define PIT_CTRL	0x0043
#define PIT_CNT0	0x0040

struct TIMERCTL timerctl;

#define TIMER_FLAGS_ALLOC 1 /* 已配置状态 */
#define TIMER_FLAGS_USING 2 /* 定时器运行中 */

void init_pit(void)
{
	int i;
	struct TIMER* t;
	io_out8(PIT_CTRL, 0x34);
	io_out8(PIT_CNT0, 0x9c);
	io_out8(PIT_CNT0, 0x2e);
	timerctl.count = 0;
	for (i = 0; i < MAX_TIMER; i++) {
		timerctl.timers0[i].flags = 0; /* 没有使用 */
	}
	t = timer_alloc(); /* 取得一个 */
	t->timeout = 0xffffffff;
	t->flags = TIMER_FLAGS_USING;
	t->next = 0; /* 末尾 */
	timerctl.t0 = t; /* 因为现在只有哨兵，所以他就在最前面*/
	timerctl.next = 0xffffffff; /* 因为只有哨兵，所以下一个超时时刻就是哨兵的时刻 */
	return;
}

struct TIMER* timer_alloc(void)
{
	int i;
	for (i = 0; i < MAX_TIMER; i++) {
		if (timerctl.timers0[i].flags == 0) {
			timerctl.timers0[i].flags = TIMER_FLAGS_ALLOC;
			return &timerctl.timers0[i];
		}
	}
	return 0; /* 没找到 */
}

void timer_free(struct TIMER* timer)
{
	timer->flags = 0; /* 未使用 */
	return;
}

void timer_init(struct TIMER* timer, struct FIFO32* fifo, int data)
{
	timer->fifo = fifo;
	timer->data = data;
	return;
}

void timer_settime(struct TIMER* timer, unsigned int timeout)
{
	int e;
	struct TIMER* t, * s;
	timer->timeout = timeout + timerctl.count;
	timer->flags = TIMER_FLAGS_USING;
	e = io_load_eflags();
	io_cli();
	t = timerctl.t0;
	if (timer->timeout <= t->timeout) {
		/* 愭摢偵擖傟傞応崌 */
		timerctl.t0 = timer;
		timer->next = t; /* 師偼t */
		timerctl.next = timer->timeout;
		io_store_eflags(e);
		return;
	}
	/* 偳偙偵擖傟傟偽偄偄偐傪扵偡 */
	for (;;) {
		s = t;
		t = t->next;
		if (timer->timeout <= t->timeout) {
			/* s偲t偺娫偵擖傟傞応崌 */
			s->next = timer; /* s偺師偼timer */
			timer->next = t; /* timer偺師偼t */
			io_store_eflags(e);
			return;
		}
	}
}


void inthandler20(int* esp)
{
	struct TIMER* timer;
	io_out8(PIC0_OCW2, 0x60); /* 把IRQ-00接收信号结束的信息通知给PIC */
	timerctl.count++;
	if (timerctl.next > timerctl.count) {
		return;
	}
	timer = timerctl.t0; /* 首先把最前面的地址赋给timer */
	for (;;) {
		/* 因为timers的定时器都处于运行状态，所以不确认flags*/
		if (timer->timeout > timerctl.count) {
			break;
		}
		/* 超时 */
		timer->flags = TIMER_FLAGS_ALLOC;
		fifo32_put(timer->fifo, timer->data);
		timer = timer->next; /* 下一定时器的地址赋给timer */
	}
	/* 新移位 */
	timerctl.t0 = timer;
	/* timerctl.next的设定 */
	timerctl.next = timerctl.t0->timeout;
	return;
}
